There is a fundamental gap in understanding how biomechanical and ergonomic factors affect drop-off and obstacle detection by blind cane users. Continued existence of this gap represents an important problem because, until it is filled, individuals with visual impairments, who are generally more prone to falls, will remain exposed to the undue risk of falls and decline in quality of life. The long-term goal of the project is to improve health outcomes of visually impaired individuals through better long cane design and cane-use biomechanics. The overall objective of this project is to obtain knowledge of how to improve ergonomic design and cane biomechanics for more dependable drop-off and obstacle detection. The central hypothesis is that ergonomic and biomechanical factors affect drop-off and obstacle detection with the long cane by blind cane users. The rationale that underlies this research is that with the knowledge obtained from the study, long canes can be redesigned and cane-use biomechanics can be altered to enable blind individuals to detect hazards on their walking paths more reliably, thus reducing the risk of falls and improving their quality of life. Guided by preliminary data, this hypothesis will be tested by pursuing two specific aims: 1) determine what ergonomic and biomechanical factors affect drop-off detection with the long cane, and 2) determine what ergonomic and biomechanical factors affect obstacle detection with the long cane. Under these aims, experimental protocols and psychophysical analysis procedures that have previously been established in the applicant's lab will be used to measure blind subjects' performance under different conditions. This proposal's experimental approach is innovative because it systematically tracks the cane and all relevant body parts, including cane shaft, cane tip, toes, knees, hips, naval, shoulders, elbows, wrists, and fingers, and directly lins their movements to objective obstacle and drop-off detection performance measures. Another innovative aspect of this project stems from its instrumentation. The use of a high- resolution infrared camera system (Optotrak Certus System) allows the researchers to track the coordinates of the body parts as well as the cane with high precision (accuracy of .1 mm in three dimensions with up to 4,600 measurements per second) in a cost-efficient manner. The proposed research is significant because reliable detection and avoidance of hazards on one's walking path can reduce the incidence of falls, which can lead to lower mortality, decreased number of emergency room visits and hospital admissions, and improved quality of life.